I've been bench running my ST G2300 and now have appx. 72 oz. of fuel thru it. My top rpm using a MA 16-8 classic prop, 10 / 18 fuel and OS-F plug is 8900 to 9000. Any leaner and the motor will sag after a few seconds. Is this acceptable top RPM or should I continue running and tweeking? All input is appreciated.